Even though he has been known for bad behavior for years, friends and colleagues speculated that things got worse since his firing from Broadway’s “Orphans.”

Producers cited “creative differences,” but the rude heave-ho marked the first time that even fellow actors called out LaBeouf’s lack of professionalism.

“He had that card, that card you get when you make films that make a lot of money that gives you a certain kind of entitlement,” Alec Baldwin opined at the time. “I think he was surprised it didn’t work in the theater.”

Labeouf in his “I am not famous anymore” paper bag.Photo: AP

Though LaBeouf now risks losing the respect of fans and professionals in the industry, he still has his supporters.

Before Thursday’s meltdown, those close to LaBeouf claimed his strange ­behavior was just an act — a Joaquin Phoenix-like performance.

“Everyone who knows Shia is in on the joke,” a Hollywood insider told Page Six earlier this year.

Thursday’s arrest is just the latest incident in a string of erratic episodes.

He recently attended the Berlin Film Festival with a paper bag over his head inscribed: “I am not famous anymore.”

He also tweeted that he was “retiring from public life because of attacks against his artistic integrity.”

And last year, after he got bounced from “Orphans,” he shared several confrontational e-mails between himself and co-stars Baldwin and Tom Sturridge.